MESSKO® MPREC®

Pressure relief device

Technical data

Design/versions
This technical document contains detailed information about the technical properties of the product. To
place an order, please use the "Bestellangabenblatt (Inquiry and order specifications)" form, which you will
1 find on our website http://www.reinhausen.com below the respective product. Further information is avail-
able in the MR Reinhausen customer portal: https://portal.reinhausen.com.

2 Protective cover with powder coating

Standard protective cover RAL 7033 (cement gray)
RAL 7038 (agate gray)
Protective cover with directed oil flow (OD cover) RAL 7033 (cement gray)
RAL 7038 (agate gray)
Spring assembly; LMPRD = Large MESSKO® Pressure Relief Device
Vent screw
3 3 Optional: Semaphore (not for offshore 1 – OPERATION position
applications) 2 – ALARM position
Offshore model (only for OD cover)

Electrical connection
No micro-switch Vertical plate without hole for standard cover;
4 screw-type blank cap for OD cover
Connection via cable screw con- 1 micro-switch 1 x M20 x 1.5 cable screw connection;
nections 1 x M20 x 1.5 dummy plug
2 micro-switches 2 x M20 x 1.5 cable screw connection
ANSI plug 1 or 2 micro-switches
Westinghouse plug 1 or 2 micro-switches
Terminal box 1 micro-switch 1 x M25 x 1.5
2 micro-switches 2 x M25 x 1,5
5 Further connections possible by request (e.g. NPT)

Sealing material Coolant Remark

NBR (standard equipment) Mineral oil Signal pin = red (anodized)
6 Viton Silicone oil, pyranol Signal pin = blue (anodized)
Mounting seal ring NBR Mineral oil Order No.: 50032703
(optional) Viton Silicone oil, pyranol Order No.: 73314900
Without mounting seal ring
7 8
Degree of protection
IP 65
IP 66, available for Standard protective cover with cable screw connection
OD cover with cable screw connection
OD cover with connection box

Maschinenfabrik Reinhausen GmbH 2022 5785291/04 EN MESSKO® MPREC® 1

 Pressure relief device MESSKO® MPREC®

Technical data
Operating conditions
Location of use Indoors and outdoors; tropic-proof
Ambient air temperature -50 °C...+80 °C (mechanical version only)
-40 °C...+80 °C (version with micro-switches)
Operating temperature -40 °C...+80 °C
Insulating fluid temperature -30 °C...+120 °C
Storage temperature -50 °C...+80 °C
Degree of protection IP66 in accordance with IEC 60529
(terminal box, cable screw con-
nections, micro-switches)
Contamination level 3
Overvoltage category III; external protection: Miniature circuit breaker maximum 16 A, C-char-
acteristic

Materials
All parts Weather-resistant and transformer oil-resistant; all external parts UV-re-
sistant
Offshore version: All external parts also seawater resistant
Device flange Seawater-proof aluminum casting
Standard protective cover Seawater-proof aluminum with powder coating RAL 7033 or RAL 7038
OD protective cover Seawater-proof aluminum casting with powder coating RAL 7033 or
RAL 7038; sealing lip in the valve plate included in the scope of delivery
Offshore version available as an option:
▪ Screws in V4A in accordance with DIN 931/933
▪ Cable screw connections in accordance with EN 60423, ISO 965
▪ Paint category CX in accordance with ISO 12944
Valve plate Stainless steel
Sealing materials ▪ NBR for mineral oil
▪ Viton for alternative insulating fluids
Springs Spring steel in accordance with EN 10270-1 SH, compression springs
with configuration-specific parts painting (in German: KTL) for identifica-
tion and as corrosion protection
Signal pin Seawater-proof aluminum; anodized
Red for standard sealing lip (NBR); blue for Viton
Vent screw Self-securing; stainless steel; wrench size 10
Semaphore Optional; corrosion-resistant steel with powder coating RAL 1026, lumi-
nous yellow; (not suitable for offshore applications)

Dimensions
Mounting Ø235 mm [Ø9.25″] bolt circle of the 6 holes Ø15.5 mm [Ø0.61″]
Protective cover Ø291 mm [Ø11.46″] standard protective cover
Ø295 mm [Ø11.61″] OD protective cover
Oil escape opening Only for version with OD protective cover:
▪ Ø90 mm [3.54″] with o-ring 95x3; bolt circle of the 3 holes Ø120 mm
[Ø4.72″]
▪ Connecting flange (available as an option) with internal thread G3 1/4″
or for welding
Height (in tripped state) Max. 234.5 mm [9.23″] standard protective cover without semaphore
Max. 340 mm [13.39″] standard protective cover with semaphore
Max. 246 mm [9.96″] OD protective cover without semaphore
Max. 342 mm [13.46″] OD protective cover with semaphore
Mounting seal ring Available as an option; Ø200 mm x Ø178.5 mm x 4.25 mm [Ø7.87″ x
Ø7.03“ x 0.17″]

2 MESSKO® MPREC® 5785291/04 EN Maschinenfabrik Reinhausen GmbH 2022

Pressure relief device MESSKO® MPREC®

Dimensions
Connection cable length for plug 1,219 mm [48″]; 1,829 mm [72″]; 2,134 mm [84″]; 2,438 mm [96″];
variant 3,658 mm [144″]; 4,572 mm [180″]; 5,004 mm [197″]; 5,080 mm [200″];
6,096 mm [240″]; 7,620 mm [300″]; 9,144 mm [360″]; 10,000 mm [394″];
11,990 mm [472″]; 15,010 mm [591″]; 20,110 mm [792″]
Weight Approx. 6 kg with standard protective cover
Approx. 11 kg with OD protective cover

Type Operating pressure

[psi] [bar] [kPa]
LMPRD 4 psi 4±1 0.28 ± 0.07 28 ± 6.9
LMPRD 5 psi 5±1 0.34 ± 0.07 34 ± 6.9
LMPRD 6 psi 6±1 0.41 ± 0.07 41 ± 6.9
LMPRD 8 psi 8±1 0.55 ± 0.07 55 ± 6.9
LMPRD 10 psi 10 ± 1 0.69 ± 0.07 69 ± 6.9
LMPRD 12 psi 12 ± 1 0.83 ± 0.07 83 ± 6.9
LMPRD 15 psi 15 ± 2 1.03 ± 0.14 103 ± 13.8
LMPRD 20 psi 20 ± 2 1.38 ± 0.14 138 ± 13.8
LMPRD 25 psi 25 ± 2 1.72 ± 0.14 172 ± 13.8
LMPRD 30 psi 30 ± 2 2.07 ± 0.14 207 ± 13.8

Micro-switches
Switch type Switch with standard contacts (silver alloy),
switch with gold-plated contacts
Contact type Standard contacts: 1 x NO (normally open contact) and 1 x NC
(normally closed contact)
or
2 x NO (normally open contact)
Gold-plated contacts: 1 x NO (normally open contact) and 1 x NC
(normally closed contact)
Housing material Seawater-proof aluminum
Rated operating voltage: Ue = 240 V
Standard contact switching ca- Max. current 10 A 30 ms
pacity in accordance with 24 V DC … 220 V DC
IEC 60076-22-1
Making capacity 130 W L/R < 40 ms
Breaking capacity 25 W L/R < 40 ms
230 V AC
Making capacity 250 VA cos φ > 0.5
Breaking capacity 60 VA cos φ > 0.5
Switching capacity, switch with 24 V DC
gold-plated contacts* Making capacity Max. 0.1 W Resistive load
Breaking capacity Max. 0.1 W Resistive load
*) Switching higher loads de-
stroys the gold layer

Maschinenfabrik Reinhausen GmbH 2022 5785291/04 EN MESSKO® MPREC® 3

 Pressure relief device MESSKO® MPREC®

Micro-switches
Switch characteristics in accor- Minimum dielectric strength, short- 2 kV, 1 min, between circuit and
dance with IEC 60076-22-1 term power supply frequency with- ground
stand voltage
1 kV, 1 min, between the contacts
in the open position
Minimum dielectric strength light- 4 kV (peak), between circuit and
ning impulse withstand voltage ground
3 kV (peak), between the contacts
in the open position

Connection via cable screw connections

Connection terminals Single-wire: 0.5…2.5 mm2, AWG 21…14; braided leads with ferrule:
0.5…1.5 mm2, AWG 21…16
Cable glands IP66 and offshore applications: M20x1.5 for cable diameters 5...14 mm;
connection cable not included in delivery
Degree of protection IP66 in accordance with IEC 60529 for enclosed devices

Connection at the terminal box

Connection terminals Single-wire: 1…4 mm2, AWG 18…12; braided leads with ferrule: 0.5…
2.5 mm2, AWG 21…14
IP66: M25x1.5 for cable diameters 11...20 mm
Offshore version: M25x1.5 for cable diameters 9...17 mm, stainless
steel
Degree of protection IP66 in accordance with IEC 60529 for enclosed devices

Connection at plug
Connection cable ANSI socket connection cable AWG 16, or
Westinghouse socket connection cable AWG 16
Degree of protection IP65 in accordance with IEC 60529 for enclosed devices

4 MESSKO® MPREC® 5785291/04 EN Maschinenfabrik Reinhausen GmbH 2022

Maschinenfabrik Reinhausen GmbH
Falkensteinstrasse 8
93059 Regensburg

+49 (0)941 4090-0

sales@reinhausen.com

www.reinhausen.com

5785291/04 EN - MESSKO® MPREC® -

F0356604 - 12/22 - Maschinenfabrik Reinhausen GmbH 2022

THE POWER BEHIND POWER.